Do I trust it? No. But I do see that possibility that it is correct. This expansion is very light on content compared to the past 3 expansions. There are no new systems that need in depth testing. Legion had class halls, artifacts, a new honor system, equalized pvp stats, major class changes like survival becoming a melee class, and the introduction of mythic +. BFA had azerite armor, communities, a different experience for both factions with leveling and the war campaign, war mode, warfronts and the updated zone to go with it, and island expeditions. Shadowlands had Torghast, Covenants, Soulbinds, conduits, legendaries, and renown system. So far all we are getting the DF is new talents, dragon riding, profession revamp, and a new class.
The new talents and class are getting the most in-depth testing currently because they allowed those who will give them constructive feedback into Alpha. Beta is hardly tested by the masses which means the next time they will get this much feedback is probably pre-patch when people actually log in to try out the changes. Plus any major balance changes really take place the first week of mythic raiding because that's when they have enough information to actually do real balance changes. Dragon Riding really doesn't need that much testing. The profession revamp really doesn't need to be perfect at launch, that can easily be tinkered with post launch. Even raid testing doesn't need to happen before pre-patch. The beta will continue and they can then open the PTR to raid test post launch. so really there is no need for an extensive beta cycle and the end of November is very likely because of it.